On Sun, 12 Feb 2006 18:01:28 +0000, Andy Dingley
wrote:

For a simple level around a whole room, I'd probably get a "whirling
spot" device. These aren't quite so visible, but they have a wider
usable arc (360°) without repositioning.

I don't know enough about these, so I have to ask. Aren't they
levelled using bubbles? If so, what's the advantage? If your eyes
are out of whack, and its' slightly tilted, you'll go full circle, but
at an angle. Also, a slight angle error is a large dimension error at
a distance. That's why I never bothered buying one. I'm curious, and
would really like to know if I'm missing something [and keep the jokes
to yourselves.]

I ran a line around my previous house, 30' square, as a baseline for
putting up siding. I used a stringline and line level. A neighbour
held the other end raising lowering from my point, and we marked our
way around the corners. I called when it was level, and he marked
ahead of me. When it came back to the first corner [I was at the
last, just marked], I called when it was level, and he called back
saying it was right on the first mark. It doesn't get better than
that for anything I'd be doing. I used a level and square to put up
ceiling tile, and you'd need a microscope to see any flaws.